But the most prominent member of Congress to promote the theory admitted Thursday it was possible that the text messages which led to the theory were sent in jest.

The theory began after the existence of text messages between FBI senior counterintelligence agent Peter Strzok and FBI lawyer Lisa Page was revealed. Strzok, who was a top investigator on special counsel Robert Mueller’s team investigating Russian interference in the 2016 election, was reassigned to the human resources office after it was discovered that he had sent text messages that could be perceived as “anti-Trump.” Those communications occurred with Page, who had worked on Mueller’s team but completed her detail before the special counsel was aware of the messages.

One of the messages contained a reference to a “secret society” within the FBI, which Republicans seized on as evidence of bias against President Donald Trump at the FBI.

Among them was Republican Sen. Ron Johnson of Wisconsin, chairman of the Senate Homeland Security Committee. On Tuesday, Johnson said during a Fox News interview that the latest messages were “further evidence of corruption – more than bias – but corruption at the highest levels of the FBI.”

Johnson said an informant provided him with information on the messages.

“And that secret society – we have an informant talking about a group that were holding secret meetings off-site,” he said. “There’s so much smoke here, there’s so much suspicion.”

Johnson then doubled-down on the comments to reporters Wednesday, saying that “the term ‘secret society’ comes from Strzok and Page,” adding however that he takes “everything … with a grain of salt.”

“I’ve heard from an individual that … there was a group of managers within the FBI that were holding meetings off site,” he continued. So “when Strzok and Page had described a secret society, that didn’t surprise me because I had corroborating information.”

The text, which Page wrote to Strzok the day after the 2016 election, appeared to be sarcastic and an attempt at humour.

“Are you even going to give out your calendars? Seems kind of depressing,” she wrote. “Maybe it should just be the first meeting of the secret society.”

CNN followed up by reporting that the calendar reference was to a gag gift of Russian President Vladimir Putin-themed calendars that one of the FBI officials purchased early in the Russia investigation. The sources added it was an attempt at humour.

On Thursday, Johnson told CNN that “it’s a real possibility” the text message was just a joke and not an indication of an anti-Trump secret society within the FBI.

The senator was widely ridiculed by both the left and right.

Republican Rep. Charlie Dent of Pennsylvania said the “secret society” conspiracy was an “Illuminati” fantasy. MSNBC host Joe Scarborough, a former Republican congressman, called Johnson’s suggestion a “reckless slur against the FBI from a pathetic lackey of Trump.”

“Does Wisconsin have recall petitions for US Senators who falsely claim a secret society exists within the FBI that is planning a coup against the president of the United States?” he tweeted. “Just curious.”

“I saw the senator … propagating this on television this morning,” he said. “It looked delusional. It looked paranoid. What began as an attempt to discredit the investigator has now devolved into delusional, self-serving paranoia.”